Mold for making an electron tube assembly



Dec. 2, 1969 Y J. T. BOYER 3,4

MOLD FOR MAKING AN ELECTRON TUBE ASSEMBLY Filed 001;. 18, 1967 FIGll II'l L FIC53 INVENTOR.

JAM ES T. BOYER wam I F l 2 ATTORNEY United States Patent ClaimsABSTRACT OF THE DISCLOSURE The disclosure is of a mold for assembling anelectron tube comprising a first disk having a rectangular apertureadapted to receive an apertured container carrying a quantity ofpowdered glass. A two-part cylindrical memher is seated on the firstdisk and has a plurality of transverse slots, with half of each slotbeing in one part and the other half being in the other part. The slotsin the twopart member are adapted to receive cathode electrodes whichhave upper leads and lower leads, with the cathodes inverted so that theupper leads penetrate through the apertures in the glass container andare embedded within the powdered glass. An apertured shield member andthen a second disk of glass or the like, which is to comprise the stemin the completed tube and having rows of apertures, are seated on thetwo-part member, with the lower leads of said cathodes each extendingthrough aligned apertures in the shield and in the glass disk. A solidcylindrical member having rows of holes extending through its length isseated on the second disk with its holes aligned with the apertures inthe disk so that the lower cathode leads can extend through the seconddisk into the holes in the cylindrical member.

A hollow open-ended tube encloses all of the abovementioned parts, and arelatively heavy member which serves as a weight caps the entireassembly.

The entire assembly is suitably heated to melt the powdered glass andthe second disk, and, when the assembly is cooled, a bond is formedbetween the glass and the upper and lower cathode leads, and a completedcathode assembly is provided. This cathode assembly can then be readilymade into a completed tube.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The presentinvention provides an improved arrangement for assembling the cathodestack in a display tube and imparting optimum strength and rigidity tothe stack.

The apparatus of the invention comprises a mold which includes aplurality of parts and which is adapted to contain a carrier forpowdered glass into which one set of cathode tabs is to be sealed, aslotted structure for supporting the cathodes themselves, and a glassdisk which receives the cathode leads and becomes the stem of the finaltube envelope. The entire assembly of mold and cathodes is heated tosoften the powdered glass and the glass disk 3,481,576 Patented Dec. 2,I969 "ice to form, on cooling, an intimate bond with the cathode tabsand leads.

DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a perspective view of a type of electrode assembly made bymeans of the mold of the invention;

FIG. 2 is an exploded view of the mold of the invention; and

FIG. 3 is a side elevational view, partly in section, of the mold of theinvention as it appears when assembled.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of the inventionis particularly suited for making an electrode assembly 10 of the typeshown in FIG. 1. Such an assembly is used in a multiple cathodeindicator tube and includes a glass stem 20 on which is seated ametallic lower shield 30 which has the form of an elongated containerand is held in place by a mica disk 40. The assembly also includes asimilar elongated upper metallic shield 50 which contains a glass block60 in which the upper tabs 70 of cathode electrodes are embedded. Theupper shield includes suitable apertures through which the tabs 70extend without touching the shield. The cathode electrodes 80 also havelower cathode tabs which extend through suitable apertures in the lowershield to the interior of the lower shield member where they are weldedto tube pins 100. The tube pins extend through the stem to which theyare secured.

The apparatus of the invention comprises a mold 102 which is shownexploded in FIG. 2. All parts of the mold are made of carbon or othersuitable materials which do not adhere to molten glass. The moldincludes a relatively large disk which includes a central aperture inwhich is seated a disk having a rectangular aperture 150. Therectangular apertured is adapted to receive the upper shield 50' of thetube assembly 10. The shield is inserted with its apertured surfacefacing up and containing a quantity of powdered glass.

Next in order, the mold includes a split cylinder comprising twoidentical halves and which have mating transverse slots 190. The slotsare adapted to receive the cathode electrodes 80 positioned upside downand with their upper tabs 70 inserted into the powdered glass in theupper shield. The cathodes have the tube pins or leads 100 welded totheir lower tabs 90 at this time. The two-part member is designed sothat the character portion of each cathode is contained within the slotsand reaches to about the upper end of the slots. The two-part cylinder160 includes a generally flat upper surface 200 surrounded by aretaining wall 210. The mica disk 40, to which the lower shield 30 issecured by suitable tabs, is threaded on the tube pins and lowercathodes tabs and is set in place on the upper end of the two-partmember with the shield down and the mica disk up. Next, the stem disk 20having suitable apertures is threaded on the tube pins and is seated onthe mica disk. A relatively large cylindrical piece 220 having apertures230 for receiving the tube pins 100 is then threaded on the tube pinsand is seated on the stem disk 20. An enclosing cylinder 240 is providedfor enclosing all of the above-described'parts, with its lower endinserted in the opening 130 in the lower disk 120 and with its upper endpositioned just below the upper end of cylinder 230 to provide a seatfor a relatively heavy disk 250' which has a central depression whichreceives the upper end of cylinder 230. The disk 250 operates as aweight to hold the parts in compression.

The mold 102, with the parts of the tube assembly 10 included asdescribed above, can be formed into a rigid unitary assembly by passingthe mold through a suitable oven which provides suflicient heat to meltthe powdered glass in the upper shield and the stem disk 20. The ovenatmosphere is preferably inert to prevent oxidation of cathode elements.When the assembly of mold and tube parts is cooled, the softened glasssolidifies to form a rigid unitary structure. Of course, it is clearthat the desired heating can be efiected in other ways, for example, bymeans of radiant energy.

What is claimed is:

1. A mold for assembling a portion of an electron tube comprising:

a plate having a rectangular aperture adapted to receive a shield meansand a quantity of powdered glass in which electrode leads are to besecured,

a two-part cylindrical member having a plurality of transverse slotswith the slots made up of a portion in one part and a potrion in theother part,

said slots being adapted to receive cathode electrodes which have upperleads and lower leads, with the cathodes being inverted so that theupper leads penetrate into said quantity of powdered glass,

an insulating disk which is to comprise the stem in the completed tubehaving rows of apertures and seated on said two-part cylinder, with thelower leads of said cathodes each extending through one aperturetherein,

a cylindrical member having rows of apertures corresponding to said rowsof apertures in said disk positioned on said disk with said lowercathode leads inserted in its apertures,

a hollow open-ended tubular member enclosing all of said parts andterminating just below the upper end of said last-mentioned tube, and

a relatively heavy member seated on said tube and on said hollowcylinder.

2. A mold for assembling a portion of an electron tube comprising:

a plate having a rectangular aperture adapted to receive a containercarrying a quantity of powdered glass, a two-part cylindrical memberhaving a plurality of transverse slots with the slots made up of aportion in one part and a portion in the other part,

said slots being adapted to receive cathode electrodes which have upperleads and lower leads, with the cathodes being inverted so that theupper leads penetrate through holes in said glass carrier and terminatewithin the powdered glass,

an insulating disk which is to comprise the stern in the completed tubehaving rows of apertures and seated on said two-part cylinder, with thelower leads of said cathodes each extending through one aperturetherein,

a cylindrical member having rows of apertures corresponding to said rowsof apertures in said disk positioned on said disk with said lowercathode leads inserted in its apertures,

a hollow open-ended tubular member enclosing all of said parts andterminating just below the upper end of said last-mentioned tube, and

a relatively heavy member seated on said tube and on said hollowcylinder.

3. The mold defined in claim 1 wherein all of said parts, except thosemade of glass or an insulating material,

are made of a heat-conductive material to which molten glass does notadhere.

4. The mold defined in claim 1 wherein all of said parts, except thosemade of glass or an insulating material, are made of carbon.

References Cited UNITED STATES PATENTS 719,744 2/ 1903 Cannon 249-91 I.SPENCER OVERHOLSER, Primary Examiner R. D. BALDWIN, Assistant ExaminerUS Cl. X.R.

